how to re connect database to wordpress

I accidentally deleted the database. Luckily it was retreived from server backup and replaced but the website won’t load and I can’t access wp-admin using http://www.mydomain.com/wp-admin (replacing mydomain with the correct name)

I have downloaded the database as a .sql file.
I have looked at wp-config and checked the database name is correct, also tried various combinations of user and password because the user should have been admin and wasn’t and the password was a code of 12 letters.

I have checked in MySql and decoded the MD5 password, and it is correct.
Also checked I am named as a user in MySql

I have checked and all wordpress folders etc are still existing, it was just the DB I deleted in error.

I expect the answer is simple, but what do I do to reconnect the database with the wordpress website?